1. Field of the Invention
The present invention relates to an AC/DC converter with piezo transformer, and more particularly, to a single stage AC/DC converter with piezo transformer.
2. Description of Related Art
In order to reduce the usage of the chemical materials, an AC/DC converter is commonly provided in the electrical apparatus which uses DC power such as battery as its operating power, such that the electrical apparatus can use the AC power provided by the power company as its operating power. In general, the AC/DC converter converts an AC power into a DC power by using an electric-magnetic converter, and the piezo electric transformer is an electric-magnetic, which is most commonly used in the AC/DC converter now.
The piezo transformer is made of a ceramic material, and its energy is transmitted by the mechanical vibrations, thus it is characterized by smaller size, non-burnable, and high electric insulation. For the back light of the color LCD, the piezo transformer is an optimum power source. However, currently the developers are unable to propose a new method for making good use of the piezo transformer. As shown in FIG. 1, a half-bridge circuit 160 is commonly used as a part of the driving circuit in the AC/DC converter 15 with piezo transformer 150.